Non-accelerator Particle Physics Research Articles

Non-accelerator particle physics in Ukraine

Non-accelerator particle physics is a new field of physics that studies the properties of particles without using accelerators. This area has been developing rapidly for the last 20—30 years providing a number of outstanding results, including the discovery of neutrino oscillations caused by the masses of neutrinos, which became the first experimental proof of an effect beyond the Standard Model of particles and interactions. While the results in the field have won five Nobel Prizes over the last twenty years, this area remains almost unnoticed in Ukraine, despite the fact that here several research groups conduct work on the subject and obtain the results of the highest quality.

Radon in the DRIFT-II directional dark matter TPC: emanation, detection and mitigation

Radon gas emanating from materials is of interest in environmental science and also a major concern in rare event non-accelerator particle physics experiments such as dark matter and double beta decay searches, where it is a major source of background. Notable for dark matter experiments is the production of radon progeny recoils (RPRs), the low energy (∼ 100 keV) recoils of radon daughter isotopes, which can mimic the signal expected from WIMP interactions. Presented here are results of measurements of radon emanation from detector materials in the 1 m3 DRIFT-II directional dark matter gas time projection chamber experiment. Construction and operation of a radon emanation facility for this work is described, along with an analysis to continuously monitor DRIFT data for the presence of internal 222Rn and 218Po. Applying this analysis to historical DRIFT data, we show how systematic substitution of detector materials for alternatives, selected by this device for low radon emanation, has resulted in a factor of ∼ 10 reduction in internal radon rates. Levels are found to be consistent with the sum from separate radon emanation measurements of the internal materials and also with direct measurement using an attached alpha spectrometer. The current DRIFT detector, DRIFT-IId, is found to have sensitivity to 222Rn of 2.5 μBql−1 with current analysis efficiency, potentially opening up DRIFT technology as a new tool for sensitive radon assay of materials.

Status of neutrinoless double beta decay searches

Neutrinoless double beta decay is one of the most sensitive tools in non-accelerator particle physics to probe the regime of physics beyond the standard model. It can provide in fact fundamental informations on the character of neutrinos and their absolute mass scale. The present status of experiments searching for neutrinoless double-beta decay (ββ(0ν)) is reviewed and the most relevant results discussed. Phenomenological aspects of ββ(0ν) are introduced. Given the observation of neutrino oscillations and the present knowledge of neutrino masses and mixing parameters, a possibility to observe ββ(0ν) at a neutrino mass scale mν in the range 10–50 meV could actually exist. The achievement of the required experimental sensitivity is a real challenge faced by a number of new proposed projects. A review of the various proposed experiments in the context of their figure-of-merit parameters is given. The most important parameters contributing to the experimental sensitivity are finally outlined. A short discussion on nuclear matrix element calculations is also given.

A first mass production of gas electron multipliers

We report on the manufacture of a first batch of approximately 2000 Gas Electron Multipliers (GEMs) using 3M's fully automated roll-to-roll flexible circuit production line. This process allows low-cost, reproducible fabrication of a high volume of GEMs of dimensions up to 30×30cm2. First tests indicate that the resulting GEMs have optimal properties as radiation detectors. Production techniques and preliminary measurements of GEM performance are described. This now demonstrated industrial capability should help further establish the prominence of micropattern gas detectors in accelerator-based and non-accelerator particle physics, imaging and photodetection.

GENIUS - a new facility of non-accelerator particle physics

The GENIUS ( Ge rmanium in Liquid Ni trogen U nderground S etup) project has been proposed in 1997 [1] as first third generation double beta decay project, with a sensitivity aiming down to a level of an effective neutrino mass of < m >∼ 0.01 - 0.001 eV. Such sensitivity has been shown to be indispensable to solve the question of the structure of the neutrino mass matrix which cannot be solved by neutrino oscillation experiments alone [2]. It will allow broad access also to many other topics of physics beyond the Standard Model of particle physics at the multi-TeV scale. For search of cold dark matter GENIUS will cover almost the full range of the parameter space of predictions of SUSY for neutralinos as dark matter [3,4]. Finally, GENIUS has the potential to be the first real-time detector for low-energy (pp and 7 Be) solar neutrinos [6,5]. A GENIUS-Test Facility has just been funded and will come into operation by end of 2001.

Connection between particle physics and space experiments

Reviewed here are some developments in instrumentation for high-energy accelerator experiments and for nonaccelerator particle physics experiments which may be of interest for space experiments. Also reviewed are some already achieved or planned space experiments which are somewhat particle physics inspired. More and more, the technical challenges of particle physics experiments offer new opportunities for other fields of science and specially for space experiments. The connection between the universe, the high-energy frontier and particle physics is more obvious every day. It is time now to also improve the connection between CERN, ESA and ESO.

Physically self-consistent basis for modern cosmology

Cosmoparticle physics appeared as a natural result of internal development of cosmology seeking physical grounds for inflation, baryosynthesis, and nonbaryonic dark matter and of particle physics going outside the Standard Model of particle interactions. Its aim is to study the foundations of particle physics and cosmology and their fundamental relationship in the combination of respective indirect cosmological, astrophysical, and physical effects. The ideas on new particles and fields predicted by particle theory and on their cosmological impact are discussed, as well as the methods of cosmoparticle physics to probe these ideas, are considered with special analysis of physical mechanisms for inflation, baryosynthesis, and nonbaryonic dark matter. These mechanisms are shown to reflect the main principle of modern cosmology, putting, instead of formal parameters of cosmological models, physical processes governing the evolution of the big-bang universe. Their realization on the basis of particle theory induces additional model-dependent predictions, accessible to various methods of nonaccelerator particle physics. Probes for such predictions, with the use of astrophysical data, are the aim of cosmoarcheology studying astrophysical effects of new physics. The possibility of finding quantitatively definite relationships between cosmological and laboratory effects on the basis of cosmoparticle approach, as well as of obtaining a unique solution to the problem of physical candidates for inflation, mechanisms of baryogenesis, and multicomponent dark matter, is exemplified in terms of gauge model with broken family symmetry, underlying horizontal unification and possessing quantitatively definite physical grounds for inflation, baryosynthesis, and effectively multicomponent dark-matter scenarios.

First tests on a large mass, low temperature array detector

A new generation of detectors for non-accelerator particle physics has been under development in the last years and has recently started to be used in experimental searches. The results have already demonstrated that low temperature detectors can be competitive with conventional ones in several fields of non-accelerator particle physics. The near future upgrading of this technique will be the extension from one single crystal device to arrays of several single crystals. This new detector set-up poses stimulating and original technical problems, both on detector structure and signal analysis: our progresses in this field are reported.

A CAMAC timing module for the use with high energy resolution detectors

A CAMAC module which measures event times with a resolution of 10 ns continuously over a period of 32.6 days has been built. The event times are stored in a deep buffer memory in form of 48-bit data words. The pulse amplitude of each event can be measured concurrently in a high resolution ADC and stored in another FIFO buffer memory. These amplitudes are tagged with a flag to correlate time with amplitude value unambiguously. In spite of the high operating frequency of 100 MHz necessitating the use of ECL counters, the module is compact (single-width) thanks to the use of TTL registers for the intermediate storage of the 48-bit time-word. The setup and testing of the modules with a NaI-pair spectrometer used in the GALLEX solar neutrino experiment is described. Other possible applications of the module in the field of non-accelerator particle physics are also mentioned.

Recent Developments in Non-Accelerator Particle Physics Experiments

Recent Developments in Non-Accelerator Particle Physics Experiments